thoughts ?

[cannucky]

Car started idling rough at the lights and popping out the tailpipes , not gunshot backfires but more like a popping paper bag , I 'm thinking it's either temperature or bad fuel as it started after a 1/2 hour drive home from the gun range seems to rev fine but idles real rough in gear { not in neutral } .Any thoughts guys .
I also tried swapping the ignition box but it started doing it again after a 20 minute drive in town .
PS plugs look good no fouling and a very light purpleish tinge on the ceramic .

 

[pettybludart]

Fuel filter dirty?Do you still have gas tank with sender?Dirty/bad sock sucking crap?Hole/leak in fuel line maybe.

 

[Princess Valiant]

when its popping...if you took the air cleaner off is it popping through the carb?

 

[Princess Valiant]

also have you tried messing with timing any ....any change if you retard or advance the timing? mainly advance

 

[Robbie2734]

What carb are you using? If it's a carter try pulling the idle adjustment screws and blow out the idle circuit. It sounds like dirt in the idle circuit.

 

[Abodybomber]

Sounds like dirt in needle and seat(primary),or dirt in the idle circuit,or blown power valve.Take a log sheet.Go side to side ,one at a time.Count the turns in ,until the needle seats.Log both sides,write it down.Pull both screws out,hit those mixture screws,with a rubber tipped blowgun( hoping you have a compressor).Re seat the needles,back out to the logged settings ,side for side. My ..02.

 

[Cudafever]

Pops continually or just once when you step on the gas?

 

[cannucky]

I 'll try to get these in order , first the tank and sender were new 4 years ago and the filter was new in august , the carb is a Holley HP950 with no choke circuit , the timing hasn't been touched and is at 15deg initial at idle in park , It starts to idle rough when I'm waiting on the light to change and then gives a muffled pop or two and seems to hesitates a little off the line but runs , it revs up with no backfires or stumbles once I get on it .
Thanks guys when the rain stops I'll look at cleaning the idle circuit and needles , sucks having a tiny 10x20 garage this time of year .

 

[65Val]

Check your float levels, Chris, when its popping and rough idling. Could be crap in the needles/seats allowing the float level to creep up too high as you're waiting at a light.

 

[Big Jim]

Might take a close look at the distributor cap for small cracks or carbon tracking-either one shows itself more in high humidity or rainy weather. Just a thought...

 

[cannucky]

I think we're on the right track but I won't know till I get a chance to pull it off and give it a good cleaning , I thought I was being smart about a month ago by dumping a bottle of Cambodian Tires fuel stabilizer in the tank but now I'm wondering if it didn't gel and foul/shellac the guts of the carb .